REFERENCE · CO-OCCURRING CONDITION
Autonomic Symptoms Alongside FND
This page covers: Palpitations, light-headedness, sweating and related bodily symptoms; arousal and upright tolerance need individual assessment.
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For the Person With FND
Understanding the body’s automatic regulation
The autonomic nervous system helps regulate heart rate, blood pressure, temperature and digestion without deliberate effort. Symptoms can include a racing heart, light-headedness, sweating or feeling unwell when upright. These experiences are real, but they do not all have the same cause. FND studies report varied autonomic findings, not one pattern that can diagnose the condition. [1][2]
A useful commonality is the interaction between bodily state, attention and activity. Feeling faint or having a pounding heart can capture attention and interrupt movement or concentration; the demands of an activity may then become harder to manage. This does not mean that the person caused the symptoms by noticing them. It also does not mean every autonomic symptom is a “fight-or-flight” response. [1]
Orthostatic intolerance means symptoms worsen when upright and often improve when lying down. POTS is one specific syndrome involving an excessive sustained rise in heart rate on standing, alongside characteristic symptoms and diagnostic criteria. It is distinct from FND and may coexist with it. The useful treatment depends on which pattern is present. [2]
Management and recovery options
- Understand the measured pattern: a clinician may review lying and standing pulse and blood pressure, medicines and the history of fainting or palpitations. This helps distinguish upright intolerance from other patterns before selecting treatment. [2] [Clinical guidance]
- Use practical upright-tolerance strategies: for an assessed orthostatic problem, seated tasks, avoiding prolonged standing and planning around heat may help. If faint, get to a safe seated or lying position rather than pushing through. [2] [Clinical guidance]
- Discuss fluid, salt and compression where appropriate: these can support circulation in selected POTS patients. They are not a universal autonomic or FND prescription; kidney, heart and blood-pressure conditions can change what is safe. [2] [Condition-specific clinical guidance]
- Adapt physical rehabilitation to the pattern: some POTS plans begin with recumbent or otherwise supported activity. Coordinate with FND rehabilitation, pain and fatigue care. Delayed post-exertional worsening requires reassessment, not automatic increases. [2][3][4] [Clinical guidance; individualized adaptation]
- Discuss targeted medication if needed: selected medicines may help heart rate, blood pressure or blood-volume regulation. They require an individualized diagnosis and monitoring; there is no single “autonomic reset” drug. [2] [Condition-specific clinical guidance; evidence varies]
- Reduce unnecessary daily effort: plan seated options, rest and help with demanding tasks. If distress or arousal adds to symptoms, address it as one contributor, without using relaxation as a substitute for treating a circulatory problem. [1][3] [FND clinical consensus; individualized adaptation]
During a familiar episode: follow the agreed positioning and symptom plan. A new faint, chest pain, severe breathlessness or palpitations unlike the usual pattern needs prompt assessment, urgently if severe. Do not assume an episode is functional because FND is on the record. [2]
For the Person With FND
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Research and Sources
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For Family, Friends, and Other Supporters
Offer a seat or help the person lie safely when needed. Standing still in a queue can be more difficult than it looks. Do not turn standing time, hydration or exercise into a test of willingness, and respect the person’s agreed clinical plan.
For the Person With FND
For Family, Friends, and Other Supporters
For Clinicians and the Care Team
Research and Sources
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For Clinicians and the Care Team
Assess orthostatic physiology and relevant alternatives before assigning a mechanism. Distinguish POTS, orthostatic hypotension, vasovagal episodes and arousal-associated symptoms where relevant. Autonomic findings in FND studies are heterogeneous and are not a clinical biomarker. Coordinate medication and activity recommendations across services. [1][2]
For the Person With FND
For Family, Friends, and Other Supporters
For Clinicians and the Care Team
Research and Sources
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Research and Sources
Evidence reviewed: September 23, 2026. POTS management evidence applies to diagnosed POTS, not to all bodily symptoms in FND. Research on autonomic profiles does not prove a single stress-based explanation or establish a universal rehabilitation protocol.
Technique labels describe the evidence for the named condition. A treatment working does not confirm an FND diagnosis or prove a shared mechanism.
| No. | Source and stable record | What it supports and limits | Figure |
|---|---|---|---|
| 1 | Paredes-Echeverri S, Maggio J, Bègue I, Pick S, Nicholson TR, Perez DL. Autonomic, endocrine, and inflammation profiles in functional neurological disorder: a systematic review and meta-analysis. Journal of Neuropsychiatry and Clinical Neurosciences. 2022;34(1):30–43. https://doi.org/10.1176/appi.neuropsych.21010025 FND-CIT-0064 | Systematic review of FND autonomic profiles; heterogeneous group findings, not individual diagnostic evidence. | — |
| 2 | Raj SR, Fedorowski A, Sheldon RS. Diagnosis and management of postural orthostatic tachycardia syndrome. CMAJ. 2022;194(10):E378–E385. https://doi.org/10.1503/cmaj.211373 FND-CIT-0074 | POTS clinical review; applies to diagnosed POTS, not all autonomic symptoms. | — |
| 3 | Nicholson C, Edwards MJ, Carson AJ, et al. Occupational therapy consensus recommendations for functional neurological disorder. Journal of Neurology, Neurosurgery & Psychiatry. 2020;91(10):1037–1045. https://doi.org/10.1136/jnnp-2019-322281 FND-CIT-0011 | Occupational therapy consensus for FND; practical adaptation, not proof of a specific component effect. | — |
| 4 | National Institute for Health and Care Excellence. Myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome: diagnosis and management. NG206. Recommendations. Accessed September 23, 2026. FND-CIT-0206 | ME/CFS guideline: energy management is not a cure; fixed incremental exercise programmes are not recommended. Does not establish the cause or treatment of all FND-associated fatigue. | — |
For the Person With FND
For Family, Friends, and Other Supporters
For Clinicians and the Care Team
Research and Sources
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